"The Hershey-Chase experiment was a series of experiments, conducted in 1952 by Alfred Hershey and Martha Chase. It identified DNA to be the genetic material of phages and, ultimately, of all organisms. Before this experiment was conducted, it was suspected that proteins were the genetic material in viruses, not DNA. A bacteriophage is a small virus that infects bacteria. It consists of a protein coat that encloses the genetic material. When a phage infects a bacterium, it inserts its genetic material into the bacterium, while its coat remains outside." ~https://br.answers.yahoo.com/question/index?qid=20080328174055AAMvFCw maybe this can help
